• Korean Journal of Food Science and Technology
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• v.20 no.6
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• pp.762-768
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• 1988

The lipolytic enzyme of milk from hormone treated and non treated cows was isolated and purified, It was shown that the crude lipase extract from the milk before and after a hormone treatment of the cows was different in color, foaming properties, yield and specific activity. Final purification of the lipase system was achieved by affinity chromatography on Heparin-Sepharose CL-6B. The lipase bound by Heparin-Sepharose was then characterised. The pH-optimum of the purified enzyme was 8.5 for butteroil emulsion as a substrate and the optimum temperature was $30^{\circ}C$ respectively. The molecular weight. determined by SDS-polyacrylamidegel electrophoresis, was about 70,000. The activity increased by 10% hen 0.01% bovine serum albumin was added to the substrate. The results indicate the enzymes obtained by affinity chromatography from milk before and after hormone treatment had the similar characteristics. The second lipolytic active component that was not bound by Heparin-Sepharose must be the cause of spontaneous rancidity.

• Korean Journal of Food Science and Technology
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• v.23 no.1
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• pp.6-14
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• 1991

Intramuscular lipid of longissimus dorsi muscle(white muscle), soleus muscle(red muscle) and cardiac muscle were autooxidized at $37^{\circ}C$ for 20 days, and the rancidity development and the effect of various factors on rancidity development were compared. Although the myoglobin content of red muscle was about 5 times as high as that of white muscle, the degree of autooxidation occurred in intramuscular lipid did not differ between red muscle and white muscle, when they had the same lipid content. Accordingly, it was suggested that the susceptibility of muscle tissues to lipid oxidation depends mainly on the lipid content of muscle tissue, regardless of muscle types. Lipid oxidation was not a major quality deterioration for dried-pork product, when it contained adequate amount of sodium nitrite and was air-tight vacuum-packed.

• Korean journal of food and cookery science
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• v.13 no.5
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• pp.609-616
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• 1997

The contents of crude lipids of Yackwa was especially high of 24.4%. After 30 days of storage, the acid value, TAB and the carbonyl value were 2.0, 1.3, and 1.4 times higher than the initial storage, respectively. Soaking in syrup prevented moisture loss and the progression from lipid oxidation to quality deterioration, and addition of ginger juice showed the slightly lower in lipid rancidity. When compared with the unsoaked group, the L value of the soaked group were lower during the 30-day storage. As for the textural changes during storage, elasticity and chewiness decreased slightly. It was hypothesized that the textural changes were affected not by the ginger juice or the storage period, but by soaking in syrup.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.3
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• pp.450-458
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• 2006

The present study was carried out to investigate the changes in chemical and sensory properties, and cholesterol lowering effect of evening primrose oil (EPO) addition in cholesterol-reduced Cheddar cheese. The cholesterol removal rate reached 92.07% by ${\beta}$-cyclodextrin in the cheese before EPO addition. The thiobarbituric acid (TBA) value of cholesterol-reduced and EPO-added cheese increased with both ripening time and amount of EPO addition. Addition of 5% EPO resulted in a significant difference in TBA value after 4-week ripening, compared with no addition of EPO. The production of short-chain free fatty acids (FFAs) increased with ripening period in all treatments. From 4 week of ripening, the amounts of short-chain FFA in 3 and 5% EPO-added groups were significantly higher than those in other groups. Among sensory characteristics, rancidity was mostly affected by EPO addition, however, the rancidity value of 1% EPO-added was not significantly different from that of EPO-free and cholesterol-reduced cheese. Also, Cheddar cheese flavor was not profoundly affected by 1% EPO addition in all ripening periods. Total blood cholesterol dramatically decreased from 184.0 to 137.1 mg/dL with 5% EPO-added and cholesterol-reduced cheese following 8 weeks of feeding. The present results indicated that 5% EPO addition resulted in a profound lowering effect on blood total cholesterol with some adverse effects on chemical and sensory properties.

• Korean Journal of Food Science and Technology
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• v.25 no.5
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• pp.517-520
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• 1993

As the pH of ground pork increased from 5.0 to 7.0, the corresponding development of 2-thiobarbituric acid reactive substance (TBARS) during storage at $4^{\circ}C$ decreased significantly (p<.001). At the 4th day of refrigerated storage, with the increase in pH of ground pork from 5.0 to 7.0, the release of free iron decreased significantly (p<.05) from 1.50 to .99 ppm. The decrease in free iron content of pH 7 pork well explains the decrease in TBARS absorbances. The fact that the addition of 2% ethylenediamine tetraacetic acid (EDTA) to pH 5 ground pork decreased the oxidative rancidity development (p<.001) strongly supported the above finding that the increased free iron content of pH 5ground pork catalyze the oxidation during storage. The activity of glutathione peroxidase (GPx) at the 4th day of refrigerated storage decreased significantly (p<.05) when the pH of ground pork decreased from 7.0 to 5.0. Both the lower free iron content and the higher activity of GPx were proved to be important factors in controlling the oxidative rancidity of high pH ground pork.

• Food Science of Animal Resources
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• v.30 no.6
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• pp.966-974
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• 2010

This study evaluated the effects of rice bran fiber (RBF) on the quality of semi-dried pork jerky (SDPJ). SDPJ was supplemented with RBF at levels of 0 (control), 1, 2, and 3%. The addition of RBF at various levels affected the composition of SDPJ except for the fat content (p>0.05). The addition of RBF at a level higher than 2% increased the protein and ash contents of SDPJ (p<0.05). The addition of RBF at various levels also affected the physiochemical properties of SDPJ (p<0.05) except for water activity (p>0.05). Increased level of RBF increased the pH. The rancidity of SDPJ was increased (p<0.05) regardless of the RBF level, whereas the metmyoglobin content (%) of SDPJ was increased at a level higher than 2%. Increased level of RBF decreased the shear force (p<0.05) and the increased processing yield of SDPJ (p<0.05). Jerky made with 2% RBF scored highest for sensory properties, including color, tenderness, juiciness, and overall acceptability (p<0.05). These results indicate that SDPJ containing 2% RBF had the most acceptable quality characteristics, but further study is required to reduce the rancidity induced by the addition of RBF.

• Korean journal of food and cookery science
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• v.8 no.2
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• pp.147-154
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• 1992

This study was carried out to investigate the rancidity of deep frying foods (cuttlefish and swetpotato) in Incheon city. The samples were collected from 3 snack corners in market, and at 10, 14 and 18 o'clock. The Acid Value, Peroxide Value and TBA value of the fried products were determined and Sensory Evaluation was also performed. The results are as follows: 1. The range of Acid Value was 0.73~1.91 on cuttlefish and 0.33~1.03 on sweetpotato. There was no significant difference in all samples by times and places. 2. The range of Peroxide Value was 3.26~8.23 on cuttlefish and 3.45~11.63 on sweetptato. There was no significant difference in all samples by times and places. 3. the range of TBA Value was 50.03~132.27 on cuttlefish and 30.63~112.83 on sweetpotato. The TBA Value of the products in department store at 18 o'clock more less than mat at 10 o'clock. 4. The Acid Value and TBA Value of sweetpotato was more less than those of cuttlefish. 5. In sensory evaluation, mere was no significant difference by times but significant difference by places on all items. 1) In greasy taste, the first one among cuttlefish products was mat of department store and last one was market product which was much more greasy taste. Among sweetpotato products, the products of department store and near-college were more less greasy man market product. 2) In flavor and overall quality, the product of department store was better than near-college and market products on all samples, 3) In color, the products of department store and near-college were more light man market products on all samples. 4) There was correlation between color and flavor, and overall quality flavor. The flavor and color of products have the effect on the overall quality of products.

• Journal of the Korean Society of Food Science and Nutrition
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• v.11 no.4
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• pp.37-41
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• 1982

In order to determine the optimal condition for making Yugwa (one of the Korean traditional cake) the textures in various conditions were studied by sensory test and texturometer. The changes of texture and fat content in the cake were measured along the period of storage. The results were as follows: (1) The cake were classified in 3 groups according to the leavening agent used in the procedure, namely refined rice wine (W), distilled liquor (L) and yeast group (Y). It was the refined rice wine group that had been 'the best' by sensory test. Its brittleness $(1.40{\pm}0.27)$ was higher than those of L and Y. (2) Crispness measured by bend test prior to soaking into syrup were 1.19, 1.23 and 1.63 in W, L, Y, respectively. (3) Chemical composition (%dry basis)) of Yugwa leavened with W included 9.3 of moisture, 1.3 crude protein, 6.7 crude lipid, 66.4 carbohydrate and 16.3 crude ash. (4) Brittleness decreased gradually along the period of storage while the rancidity increased. From the 40th days of storage, the change of brittleness and rancidity were marked as well as the scores of sensory test decreased significantly. (5) Content of linoleic acid in Yugwa decreased along the period of storage from 52.5% of total fatty acid on the first day to 10.9% on the 50th days Main fatty acids in Yugwa were oleic acid, palmitic acid and stearic acid, all of which were also decreased in content along the period of storage. One remarkable change was the appearance of an unknown fatty acid with 19.54 of retention time, in 50% of total fatty acid, on the 50th day of storage.

• Korean Journal of Medicinal Crop Science
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• v.25 no.5
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• pp.296-304
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• 2017

Background: Sancho oil extracted from Zanthoxylum schinifolium (Siebold & Zucc) is a useful edible oil that has been in use for a long time, but it is known to be susceptible to rancidity. Sancho oil purification can remove impurities to prevent rancidity. This study was performed in order to improve the quality of sancho oil and enhance its availability throughout the purification process. Methods and Results: Sancho oil extracted in Hadong, Korea was refined via the degumming and deoxygenation processes, following which we examined the changes in the polyphenol content, fatty acid content and antioxidant activity of the oil. Acetic acid was effective for deoxygenation of sancho oil and 2 N NaOH was effective for its deoxidation. The polyphenol content and antioxidant activity were reduced by the purification process. Saturated fatty acids contents did not vary with the degumming and deoxygenation processes, however the content of unsaturated fatty acids were slightly reduced. Conclusions: This study suggests that the process of sancho oil purification used in this study will contribute to the increased use and storage of sancho oil.

• Animal Bioscience
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• v.35 no.2
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• pp.290-298
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• 2022

Objective: This study was conducted to investigate the effects of adding oregano (Origanum syriacum L.) and germander (Teucrium polium L.) to poultry diets individually and/or in combination: i) on cooked chicken meat quality and storage stability, ii) to compare this effect with those of the synthetic antioxidant butylated hydroxyanisole (BHA) and with the normal basic diet (Control: without supplements). Methods: Broilers (140 birds) were raised for 21 days and then equally divided into five different treatment groups of 28 birds each. The dietary treatments were as follows: i) control; ii) germander (GER, 1.5%); iii) oregano (ORE, 2.5%); iv) combination of GER and ORE (CM, 1.5%, and 2.5%); v) BHA (0.02%). Meat patties from the five treatments were prepared, cooked, and stored at 4℃ prior to analysis. During storage, samples were measured for thiobarbituric acid-reactive substances (TBARS) and total carbonyl levels at 0, 4, and 7 days. In addition, cooked thigh meat was prepared separately to evaluate cooking loss and sensory attributes. Results: The CM dietary treatment showed the highest antioxidant effect, with decreasing TBARS values (breast and thigh meat) throughout the storage time (4 to 7 days). Furthermore, ORE showed a higher antioxidant effect, decreasing the rancidity development (TBARS values), compared to the GER during the storage period (days 0 to 7). The anti-carbonyl effect of the CM supplement was the highest among all treatments from day 0 to 7. Generally, the antioxidant effect of GER was lower compared to that of ORE and BHA alone. The CM treatment most significantly decreased off-odor and rancidity development, with the lowest oxidation odor scores. Conclusion: The results indicate that the combination of oregano and germander in the diet of boilers improves meat quality and prolongs shelf life.